DelegatingLayout.java

public class DelegatingLayout extends FrameLayout {

    private boolean mIsDelegating;
    private ViewGroup mDelegateView;
    private int[] mOriginalOffset = new int[2];

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {

        // Clear delegating flag on touch start/end
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                mIsDelegating = false;
                mOriginalOffset[0] = 0;
                mOriginalOffset[1] = 0;
        }

        // If we're delegating, send all events to the delegate
        if (mIsDelegating) {
            
            // Offset location in case the delegate view has shifted since we last fed it a motion event.
            ev.offsetLocation(mOriginalOffset[0] - mDelegateView.getLeft(), mOriginalOffset[1] - mDelegateView.getTop());
            
            return mDelegateView.dispatchTouchEvent(ev);
        }

        // Check if the delegate wants to steal touches.
        mIsDelegating = mDelegateView.onInterceptTouchEvent(ev);

        if (mIsDelegating) {

            // If delegate has stolen, we should cancel any touch handling in our own view.
            MotionEvent cancel = MotionEvent.obtain(ev);
            cancel.setAction(MotionEvent.ACTION_CANCEL);
            super.dispatchTouchEvent(cancel);
            cancel.recycle();

            // May be more complicated to handle other edge cases
            // (i.e. non shared parent view descendants, translation, etc.)
            //
            // I would use getLocationInWindow to cover more cases, but
            // the current issue only touches getTop() so this simple efficient solution is fine.
            mOriginalOffset[0] = mDelegateView.getLeft();
            mOriginalOffset[1] = mDelegateView.getTop();
            
            // Send the touch event to the delegate
            return mDelegateView.onTouchEvent(ev);
        }

        // No delegation, handle like usual.
        return super.dispatchTouchEvent(ev);
    }
}